An injection mold with automatic thread release

Abstract

This invention discloses an automatic unscrewing injection mold, comprising an upper mold mechanism, a lower mold mechanism, and a drive mechanism. The lower mold mechanism includes an upper template, a backing plate, a fixed plate, and a movable plate. A mold core is located at the top of the upper template. A lifting cavity is located in the backing plate. A molding component is inserted through the center of the mold core. The molding component includes a core rod and a threaded forming part. The bottom end of the core rod is connected to the fixed plate. The threaded forming part is rotatably fitted onto the outside of the core rod. The bottom end of the threaded forming part extends into the lifting cavity and is equipped with a lifting gear. A push rod is located at the top of the movable plate, and the top end of the push rod extends into the lifting cavity to abut the lifting gear. The drive mechanism includes a cylinder and a rack. A drive gear and a transmission gear are mounted in the lower mold mechanism via a rotating shaft. The rack meshes with the drive gear, and the transmission gear meshes with the lifting gear. This invention, an automatic unscrewing injection mold, solves the technical problems of complex unscrewing mold structure, unreliable unscrewing, and difficult manufacturing and debugging.

Description

Technical Field

[0001] This invention relates to an injection mold with automatic unscrewing capability. Background Technology

[0002] With the widespread use of plastic products in industrial production and daily life, the demand for injection-molded products with internal threads (such as bottle caps, nuts, pipe fittings, etc.) is increasing. Injection molding of these products requires a threaded molded part in the mold, and after molding, the threaded molded part needs to be removed from the product's internal threads to ensure successful ejection.

[0003] Currently, common thread demolding methods include motor-driven rotary demolding, hydraulic motor-driven demolding, and rack and pinion drive demolding. However, existing thread demolding molds require multi-stage transmission mechanisms and have high requirements for stroke control, resulting in complex structures, large overall mold structures, high manufacturing costs, and long debugging cycles. Therefore, corresponding technical solutions are needed to address these issues. Summary of the Invention

[0004] To overcome the aforementioned deficiencies of the prior art, the present invention provides an automatic unscrewing injection mold to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the technical solution of the present invention is to design an automatic unscrewing injection mold, comprising an upper mold mechanism, a lower mold mechanism, and a drive mechanism; The lower mold mechanism includes an upper mold plate, a pad, a fixed plate, and a movable plate arranged sequentially from top to bottom. The upper mold plate has a mold core at its top, and the pad has a lifting cavity. A forming component is inserted through the center of the mold core. The forming component includes a core rod and a threaded forming part. The top of the core rod has a forming head, and the bottom of the core rod is connected to the fixed plate. The threaded forming part is rotatably sleeved on the outside of the core rod. The top of the threaded forming part has a threaded forming part, and the bottom of the threaded forming part extends into the lifting cavity and has a lifting gear. The inner wall of the lifting cavity has a retaining ring located above the lifting gear. The top of the movable plate has two push rods, the tops of which extend into the lifting cavity and are used to push against the bottom of the lifting gear. The driving mechanism includes a cylinder located outside the lower mold mechanism. The output end of the cylinder is connected to a rack. A rotating shaft is rotatably mounted in the lower mold mechanism. A drive gear and a transmission gear are mounted on the rotating shaft. The rack meshes with the drive gear, and the transmission gear meshes with the lifting gear.

[0006] Preferably, a mounting base is provided between the upper template and the pad, and a receiving groove is provided at the bottom of the mounting base. A spring is provided in the receiving groove. The spring is sleeved on the outside of the threaded forming part. The top end of the spring abuts against the top wall of the receiving groove, and the bottom end of the spring abuts against the top of the lifting gear.

[0007] Preferably, the thickness of the transmission gear is greater than the thickness of the lifting gear.

[0008] Preferably, the two push rods are symmetrically arranged on both sides of the core rod.

[0009] Preferably, the threaded part has a hollow tubular structure.

[0010] Preferably, the cylinder is connected to the side of the fixed plate via a bracket.

[0011] Preferably, the drive gear is disposed in the fixed plate, and the transmission gear is disposed in the pad plate.

[0012] Preferably, the upper mold mechanism is provided with a guide post, and the lower mold mechanism is provided with a guide sleeve that cooperates with the guide post.

[0013] The advantages and beneficial effects of this invention are as follows: It provides an injection mold for automatic unscrewing, which has a reasonable structure. A drive mechanism drives a lifting gear to rotate the threaded part, allowing the threaded part to automatically move axially and disengage from the product during rotation, utilizing its threaded engagement with the product's internal threads. This eliminates the need for additional axial drive components, significantly simplifying the overall structure, reducing the number of parts, lowering mold manufacturing costs and assembly / adjustment difficulty, while ensuring a stable and reliable unscrewing process. Furthermore, during injection molding, the push rod pushes against the lifting gear, stabilizing the position of the threaded part. During demolding, the push rod releases its pressure, allowing the threaded part to rotate and disengage. The precise timing of these actions further improves the reliability of unscrewing. Moreover, while ensuring the threaded part disengages from the product, there is no limit to the number of rotations of the lifting gear, thus eliminating travel limitations on the drive mechanism (such as a rack). This allows for a more flexible design of the drive mechanism and a more compact spatial layout. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of the lower mold mechanism in this invention.

[0015] Figure 2 yes Figure 1 A diagram showing the hidden product.

[0016] Figure 3 This is a cross-sectional schematic diagram of the lower mold mechanism in this invention.

[0017] Figure 4 This is a schematic diagram of the internal structure of the lower mold mechanism in this invention.

[0018] Figure 5 This is a schematic diagram of the molding component in this invention.

[0019] Figure 6 This is a schematic diagram of the product in this invention. Detailed Implementation

[0020] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0021] The specific technical solution of this invention is as follows: In one specific embodiment, such as Figures 1 to 6 As shown, the present invention provides an automatic unscrewing injection mold, including an upper mold mechanism, a lower mold mechanism and a drive mechanism; The lower mold mechanism includes an upper mold plate 1, a pad plate 2, a fixed plate 3, and a movable plate 4 arranged sequentially from top to bottom. The upper mold plate 1 has a mold core 5 at its top. The pad plate 2 has a lifting cavity 6. A forming component is inserted through the center of the mold core 5. The forming component includes a core rod 7 and a threaded forming part 8. The top end of the core rod 7 has a forming head 9, and the bottom end of the core rod 7 is connected to the fixed plate 3. The threaded forming part 8 is rotatably sleeved on the outside of the core rod 7. The top end of the threaded forming part 8 has a threaded forming part 10, and the bottom end of the threaded forming part 8 extends into the lifting cavity 7 and has a lifting gear 11. The threaded forming part 10 is used to form the internal thread of the product 100. The inner wall of the lifting cavity 6 has a retaining ring 12 located above the lifting gear 11. The retaining ring 12 is used to block and limit the lifting gear 11. The top of the movable plate 4 has two push rods 13. The top end of the push rods 13 extends into the lifting cavity 6, and the push rods 13 are used to push against the bottom of the lifting gear 11. The drive mechanism includes a cylinder located outside the lower mold mechanism. The output end of the cylinder is connected to a rack 14. A rotating shaft 15 is rotatably mounted in the lower mold mechanism. A drive gear 16 and a transmission gear 17 are mounted on the rotating shaft 15. The rack 14 meshes with the drive gear 16, and the transmission gear 17 meshes with the lifting gear 11. The lifting gear 11 can move up and down relative to the transmission gear 17 and maintain the meshing state.

[0022] The working steps of an automatic unscrewing injection mold according to the above solution are as follows: Step 1: The upper mold mechanism and the lower mold mechanism are closed to form a cavity. The movable plate 4 and the fixed plate 3 are in a closed state. The push rod 13 pushes the bottom of the lifting gear 11 upward, so that the thread forming part 10 of the thread forming part 8 is located in the injection working position in the cavity. Molten plastic is injected into the cavity to form product 100. The internal thread of product 100 is formed by the thread forming part 10. Step 2: After product 100 is formed and cooled, first open the parting surface between the movable plate 4 and the fixed plate 3. The movable plate 4 drives the push rod 13 to move downward, and the top of the push rod 13 releases its abutment against the bottom of the lifting gear 11. Step 3: Start the cylinder to drive the rack 14 to move linearly. The rack 14 drives the drive gear 16 to rotate. The drive gear 16 drives the transmission gear 17 to rotate through the rotating shaft 15. The transmission gear 17 drives the thread forming part 8 to rotate through the lifting gear 11. Since the product 100 is fixed in place by the forming head 9 and cannot rotate with the thread forming part 8, the thread forming part 8 moves axially relative to the product 100 through the threaded engagement during the rotation. The thread forming part 10 gradually exits from the internal thread of the product 100, completing the unthreading action. Step 4: After unscrewing, open the parting surface between the upper and lower mold mechanisms. Then, start the ejection mechanism to eject product 100. Step 5: After product 100 is ejected, the movable plate 4 and the fixed plate 3 close again. The movable plate 4 drives the push rod 13 to push the lifting gear 11 upward. The lifting gear 11 drives the threaded forming part 8 to move upward. The threaded forming part 10 re-enters the injection working position in the cavity. The push rod 13 maintains its push against the lifting gear 11, and the mold enters the next injection cycle.

[0023] In another specific embodiment, such as Figures 1 to 6 As shown, a mounting base 18 is provided between the upper template 1 and the pad 2. The bottom of the mounting base 18 is provided with a receiving groove. A spring 19 is provided in the receiving groove. The spring 19 is sleeved on the outside of the threaded forming part 8. The top end of the spring 19 abuts against the top wall of the receiving groove, and the bottom end of the spring 19 abuts against the top of the lifting gear 11.

[0024] The above solution addresses the issue that during the unscrewing process, when the threaded part 8 is about to disengage from the internal thread of the product 100, the extremely short engagement section makes it difficult for the product 100 thread to exert sufficient axial force on the threaded part 8, resulting in the last small section of thread not completely breaking off. This can easily damage the product 100 thread during ejection. The present invention addresses this by incorporating a mounting base 18, a spring 19, and other structures. When the mold closes, the push rod 13 presses against the lifting gear 11, compressing the spring 19. During the unscrewing process, the spring 19 continuously applies a downward thrust to the lifting gear 11. When the threaded part 10 retracts to only the last small section of thread remaining, the extremely short engagement section significantly reduces the axial force of the product 100 thread on the threaded part 8. At this point, the spring force of the spring 19 pushes the lifting gear 11 and the threaded part 8 downwards rapidly, causing the threaded part 10 to completely disengage from the internal thread of the product 100, ensuring complete thread breakage and preventing damage to the product 100 thread during ejection. This ensures better quality control of the product 100.

[0025] In another specific embodiment, such as Figure 4 As shown, the thickness of the transmission gear 17 is greater than the thickness of the lifting gear 11.

[0026] The above solution ensures that the lifting gear 11 remains engaged with the transmission gear 17 during the lifting process, avoiding engagement disengagement caused by the lifting gear 11's movement and reducing the design requirements of the transmission structure.

[0027] In another specific embodiment, such as Figure 4 As shown, the two push rods 13 are symmetrically arranged on both sides of the core rod 7.

[0028] The above-mentioned approach was adopted to ensure a balanced jacking force.

[0029] In another specific embodiment, such as Figure 3 and Figure 5 As shown, the threaded part 8 has a hollow tubular structure.

[0030] In another specific embodiment, such as Figure 1 As shown, the cylinder is connected to the side of the fixing plate 3 via the bracket 20.

[0031] In another specific embodiment, such as Figure 3 and Figure 4 As shown, the driving gear 16 is disposed in the fixed plate 3, and the transmission gear 17 is disposed in the pad plate 2.

[0032] In another specific embodiment, such as Figure 1 As shown, the upper mold mechanism is provided with a guide post, and the lower mold mechanism is provided with a guide sleeve 21 that cooperates with the guide post.

[0033] The above solution aims to improve the motion accuracy and stability of the upper and lower mold mechanisms during the mold opening and closing process.

[0034] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An automatic unscrewing injection mold, comprising an upper mold mechanism, a lower mold mechanism, and a drive mechanism, characterized in that: The lower mold mechanism includes an upper mold plate, a pad, a fixed plate, and a movable plate arranged sequentially from top to bottom. The upper mold plate has a mold core at its top, and the pad has a lifting cavity. A forming component is inserted through the center of the mold core. The forming component includes a core rod and a threaded forming part. The top of the core rod has a forming head, and the bottom of the core rod is connected to the fixed plate. The threaded forming part is rotatably sleeved on the outside of the core rod. The top of the threaded forming part has a threaded forming part, and the bottom of the threaded forming part extends into the lifting cavity and has a lifting gear. The inner wall of the lifting cavity has a retaining ring located above the lifting gear. The top of the movable plate has two push rods, the tops of which extend into the lifting cavity and are used to push against the bottom of the lifting gear. The driving mechanism includes a cylinder located outside the lower mold mechanism. The output end of the cylinder is connected to a rack. A rotating shaft is rotatably mounted in the lower mold mechanism. A drive gear and a transmission gear are mounted on the rotating shaft. The rack meshes with the drive gear, and the transmission gear meshes with the lifting gear.

2. The injection mold for automatic unscrewing according to claim 1, characterized in that, An installation seat is provided between the upper template and the pad. The bottom of the installation seat is provided with a receiving groove. A spring is provided in the receiving groove. The spring is sleeved on the outside of the threaded forming part. The top end of the spring abuts against the top wall of the receiving groove, and the bottom end of the spring abuts against the top of the lifting gear.

3. The injection mold for automatic unscrewing according to claim 1, characterized in that, The thickness of the transmission gear is greater than the thickness of the lifting gear.

4. The injection mold for automatic unscrewing according to claim 1, characterized in that, The two push rods are symmetrically arranged on both sides of the core rod.

5. The injection mold for automatic unscrewing according to claim 1, characterized in that, The threaded part has a hollow tubular structure.

6. The injection mold for automatic unscrewing according to claim 1, characterized in that, The cylinder is connected to the side of the fixed plate via a bracket.

7. The injection mold for automatic unscrewing according to claim 1, characterized in that, The driving gear is located in the fixed plate, and the transmission gear is located in the pad plate.

8. The injection mold for automatic unscrewing according to claim 1, characterized in that, The upper mold mechanism is provided with guide posts, and the lower mold mechanism is provided with guide sleeves that cooperate with the guide posts.

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